1. Field of the Invention
Embodiments of the present invention generally relate to illumination estimation using natural scene statistics.
2. Description of the Related Art
White balance is the process of removing unrealistic color cast from a digital image caused by the color of the illumination. Human eyes automatically adapt to the color of the illumination, such that white will always appear white. Unfortunately, image capture devices (e.g., camera sensors) cannot adapt automatically. Therefore, white balance techniques are needed for image sensors in image capture systems (e.g., a digital camera) to compensate for the effect of illumination.
Automatic white balance (AWB) in digital cameras typically includes two parts: illumination estimation and white balance correction. Illumination estimation is the first and most important step in AWB. After scene illumination is estimated, the corresponding white balance correction gains are estimated, and the gains are applied to the raw image, which completes the process of white balancing an image. One significant challenge in some AWB techniques is that images with dominant non-neutral object color tend to bias the AWB decision in the direction of an incorrect illumination.